Additive manufacturing (AM) refers to a process by which digital 3D design data is used to build up a component in layers by depositing material. Additive manufacturing includes 3D printing and other processes described in more detail below. AM is a manufacturing technique which may be distinguished from conventional methods of manufacturing which require material removal. Instead of milling a workpiece from solid block, for example, additive manufacturing builds up components layer by layer using materials which may be provided in fine powder form. A range of different metals, plastics and composite materials may be used in the various additive manufacturing processed discussed herein.